Water cooled grate bar



Sept. 5, 1939. M. A. HOFFT 2,171,848

WATER COOLED GRATE BAF Filed March 5, 1957 INVENTOR.

ATTORNEYS flew-ice 21 3/0/71,

Patented Sept. 5, 1939 UNITED STATES PATENT OFFIQE 1 Claim.

My invention relates to improvements in furnace grates and particularly to furnace grates of the pusher type, adapted primarily for use in the burning of fuel such as refuse, waste, rubbish,

garbage and other like materials.

In grates of this character, the grate bars, under the influence of the intense heat developed in the burning of fuels of the above-mentioned characteristics, are apt to become warped or become expanded to such an extent that the associated parts stick together, preventing the operation, or at least the free operation, of the pusher members.

Furthermore, in grates of this character, the

fuel, particularly where the fuel consists of refuse and the like, under the intense heat, is apt to form into a hard slag which is extremely difficult to remove and which materially affects the operation of the grate.

It is one of the objects of my invention to provide a grate bar which may be used in grates for burning the above-described fuels and which will and does materially reduce the temperature of the grates to such an extent that the abovementioned objections are overcome.

For the purpose of disclosing my invention, I have illustrated an embodiment thereof in the accompanying drawing, in which:

Fig. 1 is a side elevation of a grate bar embodying my invention;

Fig. 2 is a plan of a plurality of such bars;

Fig. 3 is a sectional view taken on the line 33 of Fig. 1;

Fig. 4 is a sectional view taken on the line 44 of Fig. 1; and

Fig. 5 is a sectional View taken on the line 55 of Fig. 1.

In the embodiment illustrated, each grate bar comprises a comparatively deep narrow rib or plate I which, at its rear end, is preferably deeper than at its front end. This plate or rib is made hollow in cross section and tapers from its top portion 2 to its bottom portion 3 to an extent that the bottom portion of the rib is somewhat narrower than the top portion. Both the top and bottom edges of the rib are rounded as at 4 and 5. The upper edge of the rib carries along its sides a series of laterally extending separate teeth 6 and at its front edge, these teeth are laterally extended as at I to provide a wider set of teeth at this point for a purpose more fully hereinafter to appear. At the opposite end of the plate, the plate or rib l is provided with downwardly and rearwardly inclined notches 9 5 which form pockets or trunnion grooves for the pusher plates. The rear end of the grate bar has formed integrally with the plate or rib l a footing plate H! which, in lateral extent, equals the transversely extending ribs 1, and this footing plate III on its under side has a rabbet H which rests upon the upper edge of the bridge plate of the furnace structure.

At each end of the rib or plate I, I provide in- 5 let and outlet openings l2 and i3 into which are adapted to be threaded couplings l4 and i5 adapted to be connected with suitable circulating connecting headers as Hi.

In assembly, the grate bars are arranged side 10 by side, the footing plates it abutting one another and the transversely extending ribs filling the adjacent space between the grate bars. Interposed between the open space between the grate bars, I arrange pusher plates or fingers I? 15 which may be extended downwardly as at 13 between the grate bars. These pusher plates are provided on their opposite faces with trunnion pins 19- and suitable means in the form of arms 20, or the like, are provided whereby the pusher 20 plates may be rocked upwardly and forwardly on these trunnion pins for the purpose of pushing the fuel along the grate.

Preferably, the extended fingers l are connected by cross bars such as 2! to lend additional 25 strength to these extending fingers.

It will be noted that the distance between the centers of the pusher fingers H or the distance between the trunnion slots 9 is considerably greater than the length. of a pusher. Due to this 30 spacing, I am enabled to provide a spacing between the pushers which will permit clearance between the operating arms of the successive pushers to permit a greater movement of the pushers toward a vertical position. Furthermore, 35 it will be noted that this spacing is filled by the wider laterally extending teeth I! so that there is no danger of fuel dropping between the grates.

I claim as my invention:

As a new article of manufacture, a grate bar 40 comprising a comparatively deep vertical hollow rib having its upper surface rounded and having its sides flat and inclined downwardly toward one another to provide the water circulating passage therein, said rib having a plurality of laterally 45 projecting teeth adjacent its upper edge, the teeth being substantially fiat on their upper surfaces and having their top surfaces coincident with the top edge of said grate bar, a plurality of trunnion receiving sockets formed in the upper face of said rib and a plurality of laterally projecting filler members adjacent the upper edge of the rib and of greater lateral extent than the teeth, said filler members having their top surfaces flattened and lying in the same plane as the teeth and being positioned adjacent the trunnion openings.

MAURICE A. HOFFT. 

